Highlights

The confusion around HTML5, xaml and Jupiter is finally cleared up.
The new immersive apps (full screen, metro style apps which are launched from the tile based interface) can be built in either C#/XAML or HTML5/JS. Under the covers it reflects into the WinRT APIs. Apps built like this will run on ANY Win8 machine (x86, ARM, etc)

Silverlight & WPF are “legacy”. They put it onto the slide for show. The Win8 xaml looks to be 90% compatible with Silverlight. Demos are shown where they take a Silverlight app, copy/paste the code into a new Win8 XAML app, and only a few namespaces need to be changed. A silverlight grid is then changed to use the native WinRT grid to make it touch enabled and “Metro-y”

The Win8 XAML app is ported to Windows Phone 7 with only 1 line changed.

New version of Visual Studio available to help build apps for Win 8 “Microsoft Visual Studio 11 Express for Windows Developer Preview” (got to love Microsoft product names)

Expression blend works for editing the HTML5/JS apps

The native WinRT controls work in XAML and HTML5

New windows 8 app store. Store & submission process VERY similar to Windows Phone 7. Can submit via Visual Studio
Paul Thurrott: “Biggest point of Windows Store: Microsoft is NOT taking a 30 percent cut. It will take a ZERO percent cut.”

Win8 machines can be easily restored back to a “clean base image” that developer can specify. Keeps all files, just reverts apps. (Reset/Refresh)

Windows Live application integration. Nice support for photos, calendar, mail, people. Very similar to Windows Phone 7 built in features.
Windows user account settings Synced across PCs via the cloud (profile photo, etc)

Win8 specs are the same as Win 7. Consumes less memory after startup.
Boot times have been massively reduced. Cold boot demo shows the PC almost starting faster than the monitor can turn on.